In recent years, there have been developed electronic wrist watches of self-winding electric power generation type mounted with a self-winding electric power generation device for converting the mechanical energy of the rotary weight to electrical energy.
An electric power generation watch having a self-winding electric power generation device heretofore proposed has, in the watch case, a time indication train wheel including a third wheel, a fourth wheel, a fifth wheel and so on, a time correction train wheel including minute wheel and so on, a speed increasing train wheel for electric power generation including an electric power generation intermediate wheel, and motors for driving these train wheels. And these train wheels and motors are disposed in the watch case so as not to overlap each other.
Furthermore, the motor for electric power generation disposed in the case is formed so as to become slender in order to improve the electric power generation efficiency of the electric power generation device. This slender motor for electric power generation is mounted on a ground plate in such a position as not to interfere with the above described train wheels and other motors.
Heretofore, such electric power generation watches having an electric power generation function have been proposed in Japanese Patent Application Laid-Open No. HEI-7-333360 and Japanese Patent Application Laid-Open No. HEI-5-323051.
Incidentally, such electronic wrist watches of self-winding electric power generation type are rapidly spreading in recent years. With the spread of the self-winding electric power generation watches, there are demanded electric power generation watches of multi-function type having an additional function, such as a chronograph function, other than the ordinary time indication function, besides the self-winding electric power generation function.
Here, in the multi-function wrist watch having an additional function such as a chronograph function, besides components which is used for time indication of the ordinary wrist watch which has no electric power generation function, components which are used for an additional function, such as a train wheel for chronograph, are mounted on the watch case of such a multi-function wrist watch.
In the conventional electric power generation watch having a self -winding electric power generation device, however, train wheels for time indication, time correction, and electric power generation, and a plurality of motors for driving these train wheels are disposed in the watch case with no space as described above. Within this case, there is no space for disposing a multi-hand structure for the chronograph or the like and other components of the multi-function structure.
In other words, in the conventional self-winding electric power generation watch, the train wheels and motors performing the original function of the electric power generation watch, such as the time indication function and the electric power generation function, are disposed so as to occupy the entire space on the ground plate ranging from the center portion of the watch to the peripheral portion. Therefore, it is difficult to add the additional function structure thereto from the viewpoint of the two-dimensional space. Furthermore, if it is attempted to mount the additional function structure above or under the train wheels and motors, it becomes impossible to support the train wheel for electric power generation and the train wheel for the additional function within the case via shafts.
In the conventional self-winding electric power generation watch, therefore, it is difficult to mount the additional function structure such as the chronograph structure from the aspect of space so long as a large sized ground plate and a large sized case exceeding a range permitted as a wrist watch are not provided. Until now, production of a self-winding electric power generation watch having the additional function has not been realized.
An object of the present invention is to provide a self-winding electric power generation watch having an additional function structure which is free from the above described drawbacks of the conventional self-winding electric power generation watch, which is prevented from becoming large in size of the entire watch by efficiently disposing the train wheels for watch, electric power generation, and additional function, and motors for driving these wheels in a watch case, and which is capable of having a further additional function in the self-winding electric power generation watch.